Data packet transmission in multipoint-to-multipoint networks (e.g., ad-hoc or mesh networks) is usually arranged by sending one or more data packets. A data packet is often encoded and modulated. Also, a data packet typically includes at least one frame. Each frame is preceded by a preamble. The primary purposes of the preamble include 1) enabling the receiver of the frame to detect the frame on the transmission medium, 2) adjusting the gain of the receiver (e.g., an analog front end (AFE)) and synchronizing the clock so that frame is received when expected. The frame also has a header that carries information helping the receiver to address, demodulate, and decode the frame. The preamble and header are generally followed by a payload, which carries data for communication to one or more receivers.
Because of their ubiquitous nature, powerlines are increasing in popularity as a transmission medium for many networks that use data packet transmission techniques. For example, Power Line Communication (PLC), also called Mains Communication, Power Line Transmission (PLT), Broadband Powerline (BPL), Powerband or Power Line Networking (PLN), is a term describing several different systems for using power distribution wires for simultaneous distribution of data. PLC systems can communicate voice and data by superimposing a signal(s) over standard 50 or 60 Hz alternating current (AC). For indoor applications, PLC equipment can use household electrical power wiring as a transmission medium.
Most AC power outlets have 3 connections, phase (P), neutral (N), ground (G). A PLC system can utilize two independent channels provided by these three connections (e.g., P-N pair for one channel and N-G pair for another channel). Utilizing more than two channels is also possible. Without loss of generality, only two channels are assumed in this disclosure for the simplicity of description and illustration.
A Single-Input Single-Output (SISO) PLC system often utilizes P-N pair for its communication channel because of its ubiquitous availability. However, emerging PLC Multi-Input Multi-Output (MIMO) technology takes advantage of the remaining communication channel(s) to increase spectral efficiency and throughput.
Most deployed SISO PLC modems provide a payload repetition scheme that effectively repeats payload blocks in frequency and time to increase the robustness when the channel characteristics are unknown. However, such a SISO payload repetition does not effectively translate to MIMO PLC modems and systems, as the application of the SISO payload repetition scheme would result in undesirable correlation of payloads.
The Detailed Description references the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components. Also, note that any text smaller than ten point is presented merely to indict where text would appear in the depicted figures. Since such text is merely an indicator of where text might appear, the content of such text is unimportant to the understanding the implementations depicted.